cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-6 of 6 results.

A292320 p-INVERT of (1,0,0,1,0,0,1,0,0,...), where p(S) = 1 - S - S^3.

Original entry on oeis.org

1, 1, 2, 4, 6, 12, 22, 36, 67, 122, 209, 377, 681, 1193, 2130, 3823, 6764, 12043, 21531, 38252, 68076, 121456, 216126, 384691, 685636, 1220767, 2173346, 3871747, 6894873, 12276852, 21866387, 38941846, 69344928, 123500513, 219943018, 391676701, 697538335
Offset: 0

Views

Author

Clark Kimberling, Sep 14 2017

Keywords

Comments

Suppose s = (c(0), c(1), c(2), ...) is a sequence and p(S) is a polynomial. Let S(x) = c(0)*x + c(1)*x^2 + c(2)*x^3 + ... and T(x) = (-p(0) + 1/p(S(x)))/x. The p-INVERT of s is the sequence t(s) of coefficients in the Maclaurin series for T(x). Taking p(S) = 1 - S gives the "INVERT" transform of s, so that p-INVERT is a generalization of the "INVERT" transform (e.g., A033453).
See A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(x - x^3); p = 1 - s - s^3;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A079978  *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A292320 *)

Formula

G.f.: -((1 + x^2 - 2 x^3 + x^6)/(-1 + x + 4 x^3 - 2 x^4 - 3 x^6 + x^7 + x^9)).
a(n) = a(n-1) + 4*a(n-3) - 2*a(n-4) - 3*a(n-6) + a(n-7) + a(n-9) for n >= 10.

A291035 p-INVERT of (1,0,0,1,0,0,1,0,0,...), where p(S) = 1 - S - 2 S^2.

Original entry on oeis.org

1, 3, 5, 12, 27, 58, 130, 285, 629, 1389, 3060, 6753, 14892, 32844, 72445, 159775, 352401, 777244, 1714259, 3780930, 8339090, 18392449, 40565829, 89470733, 197333940, 435233685, 959938112, 2117210180, 4669654005, 10299246171, 22715702489, 50101058976
Offset: 0

Views

Author

Clark Kimberling, Sep 14 2017

Keywords

Comments

Suppose s = (c(0), c(1), c(2), ...) is a sequence and p(S) is a polynomial. Let S(x) = c(0)*x + c(1)*x^2 + c(2)*x^3 + ... and T(x) = (-p(0) + 1/p(S(x)))/x. The p-INVERT of s is the sequence t(s) of coefficients in the Maclaurin series for T(x). Taking p(S) = 1 - S gives the "INVERT" transform of s, so that p-INVERT is a generalization of the "INVERT" transform (e.g., A033453).
See A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(x - x^3); p = 1 - s - 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A079978 *)
    Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291035 *)

Formula

G.f.: -(1 + x)*(-1 - x + x^2)/((-1 - x + x^3)*(-1 + 2*x + x^3)).
a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3) - a(n-4) - a(n-6) for n >= 7.

A291036 p-INVERT of (1,0,0,1,0,0,1,0,0,...), where p(S) = 1 - 2 S - 2 S^2.

Original entry on oeis.org

2, 6, 16, 46, 132, 376, 1074, 3066, 8752, 24986, 71328, 203624, 581298, 1659462, 4737360, 13524006, 38607732, 110215648, 314638754, 898216794, 2564189568, 7320134930, 20897197344, 59656394448, 170304435554, 486177568038, 1387918211824, 3962167507006
Offset: 0

Views

Author

Clark Kimberling, Sep 14 2017

Keywords

Comments

Suppose s = (c(0), c(1), c(2), ...) is a sequence and p(S) is a polynomial. Let S(x) = c(0)*x + c(1)*x^2 + c(2)*x^3 + ... and T(x) = (-p(0) + 1/p(S(x)))/x. The p-INVERT of s is the sequence t(s) of coefficients in the Maclaurin series for T(x). Taking p(S) = 1 - S gives the "INVERT" transform of s, so that p-INVERT is a generalization of the "INVERT" transform (e.g., A033453).
See A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(x - x^3); p = 1 - 2 s - 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A079978  *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291036 *)
    u/2 (* A291037 *)

Formula

G.f.: -((2 (-1 - x + x^3))/(1 - 2 x - 2 x^2 - 2 x^3 + 2 x^4 + x^6)).
a(n) = 2*a(n-1) + 2*a(n-2) + 2*a(n-3) - 2*a(n-4) - a(n-6) for n >= 7.

A291037 a(n) = (1/2)*A291036(n).

Original entry on oeis.org

1, 3, 8, 23, 66, 188, 537, 1533, 4376, 12493, 35664, 101812, 290649, 829731, 2368680, 6762003, 19303866, 55107824, 157319377, 449108397, 1282094784, 3660067465, 10448598672, 29828197224, 85152217777, 243088784019, 693959105912, 1981083753503, 5655510252642
Offset: 0

Views

Author

Clark Kimberling, Sep 14 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(x - x^3); p = 1 - 2 s - 2 s^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A079978  *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291036 *)
    u/2 (* A291037 *)
    LinearRecurrence[{2,2,2,-2,0,-1},{1,3,8,23,66,188},30] (* Harvey P. Dale, Sep 24 2017 *)

Formula

G.f.: -((-1 - x + x^3)/(1 - 2 x - 2 x^2 - 2 x^3 + 2 x^4 + x^6)).
a(n) = 2*a(n-1) + 2*a(n-2) + 2*a(n-3) - 2*a(n-4) - a(n-6) for n >= 7.

A291038 p-INVERT of (1,0,0,1,0,0,1,0,0,...), where p(S) = (1 - 2 S)^2.

Original entry on oeis.org

4, 12, 32, 84, 216, 544, 1348, 3300, 8000, 19236, 45936, 109056, 257604, 605820, 1419232, 3313396, 7711944, 17900320, 41445764, 95746260, 220735616, 507934276, 1166792160, 2676017408, 6128381316, 14015556588, 32012831648, 73033858964, 166434905016
Offset: 0

Views

Author

Clark Kimberling, Sep 14 2017

Keywords

Comments

Suppose s = (c(0), c(1), c(2), ...) is a sequence and p(S) is a polynomial. Let S(x) = c(0)*x + c(1)*x^2 + c(2)*x^3 + ... and T(x) = (-p(0) + 1/p(S(x)))/x. The p-INVERT of s is the sequence t(s) of coefficients in the Maclaurin series for T(x). Taking p(S) = 1 - S gives the "INVERT" transform of s, so that p-INVERT is a generalization of the "INVERT" transform (e.g., A033453).
See A291728 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(x - x^3); p = (1 - 2 s)^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A079978  *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291038 *)
    u/4 (* A291039 *)

Formula

G.f.: -((4 (-1 + x + x^3))/(-1 + 2 x + x^3)^2).
a(n) = 4*a(n-1) - 4*a(n-2) + 2*a(n-3) - 4*a(n-4) - a(n-6) for n >= 7.

A291039 a(n) = (1/4)*A291038(n).

Original entry on oeis.org

1, 3, 8, 21, 54, 136, 337, 825, 2000, 4809, 11484, 27264, 64401, 151455, 354808, 828349, 1927986, 4475080, 10361441, 23936565, 55183904, 126983569, 291698040, 669004352, 1532095329, 3503889147, 8003207912, 18258464741, 41608726254, 94722900936, 215428701233
Offset: 0

Views

Author

Clark Kimberling, Sep 14 2017

Keywords

Crossrefs

Programs

  • Mathematica
    z = 60; s = x/(x - x^3); p = (1 - 2 s)^2;
    Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A079978  *)
    u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291038 *)
    u/4 (* A291039 *)

Formula

G.f.: -((-1 + x + x^3)/(-1 + 2 x + x^3)^2).
a(n) = 4*a(n-1) - 4*a(n-2) + 2*a(n-3) - 4*a(n-4) - a(n-6) for n >= 7.
Showing 1-6 of 6 results.